// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_
#define MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_

#include <stddef.h>
#include <stdint.h>

#include "base/callback_forward.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "media/base/video_frame.h"
#include "mojo/public/cpp/system/buffer.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/size.h"

namespace mojo {
template <typename T, typename U>
struct TypeConverter;
template <typename T>
class StructPtr;
};

namespace media {

namespace mojom {
    class VideoFrame;
}

// A derived class of media::VideoFrame holding a mojo::SharedBufferHandle
// which is mapped on constructor and remains so for the lifetime of the
// object. These frames are ref-counted.
class MojoSharedBufferVideoFrame : public VideoFrame {
public:
    // Callback called when this object is destructed. Ownership of the shared
    // memory is transferred to the callee.
    using MojoSharedBufferDoneCB = base::Callback<void(mojo::ScopedSharedBufferHandle buffer,
        size_t capacity)>;

    // Creates a new I420 frame in shared memory with provided parameters
    // (coded_size() == natural_size() == visible_rect()), or returns nullptr.
    // Buffers for the frame are allocated but not initialized. The caller must
    // not make assumptions about the actual underlying sizes, but check the
    // returned VideoFrame instead.
    static scoped_refptr<MojoSharedBufferVideoFrame> CreateDefaultI420(
        const gfx::Size& dimensions,
        base::TimeDelta timestamp);

    // Creates a MojoSharedBufferVideoFrame that uses the memory in |handle|.
    // This will take ownership of |handle|, so the caller can no longer use it.
    // |mojo_shared_buffer_done_cb|, if not null, is called on destruction,
    // and is passed ownership of |handle|.
    static scoped_refptr<MojoSharedBufferVideoFrame> Create(
        VideoPixelFormat format,
        const gfx::Size& coded_size,
        const gfx::Rect& visible_rect,
        const gfx::Size& natural_size,
        mojo::ScopedSharedBufferHandle handle,
        size_t mapped_size,
        size_t y_offset,
        size_t u_offset,
        size_t v_offset,
        int32_t y_stride,
        int32_t u_stride,
        int32_t v_stride,
        base::TimeDelta timestamp);

    // Returns the offsets relative to the start of |shared_buffer| for the
    // |plane| specified.
    size_t PlaneOffset(size_t plane) const;

    // Sets the callback to be called to free the shared buffer. If not null,
    // it is called on destruction, and is passed ownership of |handle|.
    void SetMojoSharedBufferDoneCB(
        const MojoSharedBufferDoneCB& mojo_shared_buffer_done_cb);

private:
    // mojo::TypeConverter added as a friend so that MojoSharedBufferVideoFrame
    // can be transferred across a mojo connection.
    friend struct mojo::TypeConverter<mojo::StructPtr<mojom::VideoFrame>,
        scoped_refptr<VideoFrame>>;
    friend class MojoDecryptorService;

    MojoSharedBufferVideoFrame(VideoPixelFormat format,
        const gfx::Size& coded_size,
        const gfx::Rect& visible_rect,
        const gfx::Size& natural_size,
        mojo::ScopedSharedBufferHandle handle,
        size_t mapped_size,
        base::TimeDelta timestamp);
    ~MojoSharedBufferVideoFrame() override;

    // Initializes the MojoSharedBufferVideoFrame by creating a mapping onto
    // the shared memory, and then setting the strides and offsets as specified.
    bool Init(int32_t y_stride,
        int32_t u_stride,
        int32_t v_stride,
        size_t y_offset,
        size_t u_offset,
        size_t v_offset);

    // Returns the mojo shared memory handle. This object continues to own the
    // handle. Caller should call duplicate the handle if they want to keep a
    // copy of the shared memory.
    const mojo::SharedBufferHandle& Handle() const;

    // Returns the size of the shared memory.
    size_t MappedSize() const;

    uint8_t* shared_buffer_data()
    {
        return reinterpret_cast<uint8_t*>(shared_buffer_mapping_.get());
    };

    mojo::ScopedSharedBufferHandle shared_buffer_handle_;
    mojo::ScopedSharedBufferMapping shared_buffer_mapping_;
    size_t shared_buffer_size_;
    size_t offsets_[kMaxPlanes];
    MojoSharedBufferDoneCB mojo_shared_buffer_done_cb_;

    DISALLOW_COPY_AND_ASSIGN(MojoSharedBufferVideoFrame);
};

} // namespace media

#endif // MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_
